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/*
* Copyright (c) 2021, Kyle Pereira <hey@xylepereira.me>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <LibCore/EventLoop.h>
#include <LibCore/Object.h>
namespace Core {
template<typename Result>
class Promise : public Object {
C_OBJECT(Promise);
public:
Function<void(Result&)> on_resolved;
void resolve(Result&& result)
{
m_pending = move(result);
if (on_resolved)
on_resolved(m_pending.value());
}
bool is_resolved()
{
return m_pending.has_value();
};
Result await()
{
while (!is_resolved()) {
Core::EventLoop::current().pump();
}
return m_pending.release_value();
}
// Converts a Promise<A> to a Promise<B> using a function func: A -> B
template<typename T>
RefPtr<Promise<T>> map(T func(Result&))
{
RefPtr<Promise<T>> new_promise = Promise<T>::construct();
on_resolved = [new_promise, func](Result& result) mutable {
auto t = func(result);
new_promise->resolve(move(t));
};
return new_promise;
}
private:
Promise() = default;
Optional<Result> m_pending;
};
}
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